<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8"/>
    <title>React App</title>
</head>
<style>
    body{
        margin: 0;
    }
    #father{
        display: flex;
        justify-content: center;
        align-items: center;
        background: rgba(0,0,0,0.7);
        height:100vh;
    }
    #son{
        width: 80%;
        height: 60%;
        background: white;
        border-radius: 30px;
    }
</style>
<body>
<div id="father"><div id="son"></div></div>
</body>

<!-- https://blog.csdn.net/weixin_44135121/article/details/91430443 -->
</html>
